Portable metering chargers for low viscosity materials

ABSTRACT

The invention comprises a portable metering apparatus for supply of low viscosity materials in measured quantities and intended mainly for handling charges of explosive material such as ammonium nitrate and fuel oil, said apparatus comprising a hopper for the material to be metered, a horizontal cylinder located beneath the hopper and having a piston member mounted therein, which piston member includes a first and second section spaced axially apart to provide a transfer passage and a metering device into which material flows by gravity from the hopper through the transfer passage into a measuring chamber incorporated in the metering device until the piston is actuated to cut off the flow and permit discharge of a measured amount of material from said chamber. A metering plunger is adjustably mounted within the measuring chamber by which its capacity can be pre-set to measure a give quantity. The cylinder has inlet and outlet orifices for connection respectively to the hopper and the metering chamber. The piston member is urged, e.g. by spring means, to a normal or open position in which the hopper remains in communication with the metering chamber through the transfer passage to permit of transfer of material by gravity from the hopper to said chamber, pneumatically operated means being provided for effecting displacement of the piston member to an operative or release position to cut off the flow of material from the hopper and permit release of the measured quantity in the metering chamber.

United States Patent Bailly [45] July 11, 1972 [54] PORTABLE METERINGCHARGERS FOR LOW VISCOSITY MATERIALS Roger Gaston Bailly, Aubenas,France .Societe Anonyme, Societe Miniere Et Metallurgique De Penarroya,Paris, France [22] Filed: Oct. 30,1970

[21] Appl.No.: 85,608

[72] Inventor:

[73] Assignee:

Primary Examiner-Robert B. Reeves AssistanrExaminer-Larry MartinAtrorney-Mm. Melville, Strasser, Foster & Hoffmann [511 ABSTRACT Theinvention comprises a portable metering apparatus for supply of lowviscosity materials in measured quantities and intended mainly forhandling charges of explosive material such as ammonium nitrate and fueloil, said apparatus comprising a hopper for the material to be metered,a horizontal cylinder located beneath the hopper and having a pistonmember mounted therein, which piston member includes a first and secondsection spaced axially apart to provide a transfer passage and ametering device into which material flows by gravity from the hopperthrough the transfer passage into a measuring chamber incorporated inthe metering device until the piston is actuated to cut ofi the flow andpermit discharge of a measured amount of material from saidchamber. Ametering plunger is adjustably mounted within the measuring chamber bywhich its capacity can be pre-set to measure a give quantity. Thecylinder has inlet and outlet orifices for connection respectively tothe hopper and the metering chamber. The piston member is urged, e. g.by spring means, to a normal or open position in which the hopperremains in communication with the metering chamber through the transferpassage to permit of transfer of material by gravity from the hopper tosaid chamber, pneumatically operated means being provided for effectingdisplacement of the piston member to an operative or release position tocut off the flow of material from the hopper and permit release of themeasured quantity in the metering chamber.

6 Claim, 5 Drawing Figures PKTENTEDJUL 11 I972 3,575, 27

sum 1 or 4 2 2 lNVENTOR/S ROGER GASTON 5mm MELVILLE STRASSEP FOSTER &HOFFMAN attorneys P'A'TENTEDJUH 1 m2 3,675,827

lNVENTGQ/E ROGER e smu emu MELVILLE STRASSER FOSTER 8 HC FXL.

attorneys PKTE'N'TEDJUL 1 1 I972 SHEET U CF 4 lNVENTO /S ROGEP GASTON B;

PORTABLE METERING CHARGERS FOR LOW VISCOSITY MATERIALS The presentinvention relates to a portable metering apparatus or loader fordelivery of low viscosity materials in given quantities, especially ofammonium nitrate fuel oils explosive mixtures.

The apparatus permits the distribution under pressure of strictlyaccurate amounts of slightly viscous materials and finds an applicationmore particularly in the injection into drill holes, blast hole, etc..of an explosive mixture of ammonium nitrate and fuel oil. This mixtureis well known in the art under the name AN.FO (ammonium nitrate-fueloil).

Apparatus are already known for injecting materials of theabove-mentioned type under pressure, some such apparatus being describedin an article by CH. Vivian in the American publication Compressed AirMagazine of May, 1962, Volume 67, No. 5, pages 19-20. They essentiallycomprise a receptacle which contains the product to be injected andwhich is provided at its lower portion with an outlet hopper. The hopperfeeds into the vicinity of a venturi device provided in a conduit whichis connected to a source of compressed air as well as an injectionorifice. Owing to the suction effect of the venturi device, thecompressed air carries the product to the orifice and into the drill orblast hole that is being filled to a predetermined level.

In certain apparatus of this type, the explosive reservoir is sealed;air under pressure is introduced thereinto which acts as a pistonagainst the product to be injected and increases the rate of filling thedrill or blast hole.

A disadvantage of such known devices is that it is impossible to meterthe quantity of explosives that is introduced into the particular drillor blast hole. Such a disadvantage is particularly serious when dealingwith faulted ground the explosive not only fills the hole provided butalso the large faults which are in communication with this hole. It isevident that such a situation risks uncontrolled cave-ins which mayresult in serious accidents.

In order to overcome this disadvantage one might consider adapting ametering device of a generally known type to a loader of theabove-mentioned type. Such apparatus are widely used in variousindustries and are described, for example, in French Pat. No 972,145,US. Pat. No. 2,630,014 and German Pat. No. 79,533. The first comprises ahollow sliding member having a fixed capacity that is displaceable bytranslation between a filling position and an emptying position. The

second comprises a sort of ladle having an adjustable capacity owing toa helically movable bottom. The last effects a nonadjustable meteringaction by means of a space between two pneumatically movable stops.

The known devices in which the product to be injected is constantlyunder pressure impose technological limitations and increase the safetyproblems. On the other hand the known devices in which the product is atatmospheric pressure have the disadvantage of an insufficient flow.

An object of the invention is therefore to provide a metering device inwhich the reservoir contains the product to be injected which is notunder pressure and which nevertheless provides an increased flow.

Another object of the invention is to provide a metering device adaptedto inject low viscosity materials in volumetric quantities which areaccurately determined by the use in situ regardless of the dimensions ofthe hole drilled for the reservoir.

A supplementary object of the invention is to provide a metering deviceparticularly suitable for the injection of a AN.FO mixture in the drillor blast hole.

The metering apparatus of the invention comprises in combination ahopper, which is preferably cylindro-conical, a distributing device towhich material from the hopper is transferred by gravity and including ahorizontal cylinder in which operates a double piston member andpneumatically operating means for effecting displacement of the pistonto and from an operative position in which material passes from thehopper to a metering device, the said device conveniently being mountedimmediately beneath the said cylinder and comprising a verticalcylindrical body part having a metering chamber in which is adjustablymounted a metering plunger so that by adjusting the position of theplunger the capacity of the chamber can be adjusted, and accordingly thevolume of material which will be discharged or otherwise releasedtherefrom by evacuating it, preferably using air pressure, through amanifold or outlet at the bottom of the metering chamber, at the sametime as the piston is moved to close the outlet opening of the hopper.

The piston member is normally held by spring means in a position inwhich the outlet from the hopper is open to allow material to flow bygravity into the measuring chamber, and is moved to an operative orclosing position by compressed air admitted into the cylinder of thepiston under the control of a valve-cock.

Adjustment of the metering plunger may be effected by a rotary pointerwhich is fast therewith and co-operates with a helical cam face in or onthe wall of the metering body. The pointer may be provided by a screwand wing nut so that by releasing the latter the position of the screwwhich projects through a slot in the wall of the cylinder may beadjusted to give the required volume of material to be admitted into themetering device.

The invention is illustrated in the attached drawings, in which:

FIG. 1 is an elevation and FIG. 2 a plan view of the metering apparatusor loader in accordance with one embodiment of the invention;

FIG. 3 is a side view in the direction of arrow F of FIG. 1;

FIG. 4 is a section on line lV-IV of FIG. 3 showing the apparatus atrest with piston in its operative or open position;

FIG. 5 is a similar cross-section, but showing the apparatus in positionof evacuation of the metered amount of material.

Referring to FIGS. 1 and 2, the apparatus comprises a circular hopper 1supported on three legs 2, the base terminating in a truncated conicalportion (FIG. 1) from which material to be metered, e.g., a mixture ofammonium nitrate and fuel oil in grain form, as in the example selected,is delivered to the metering system or device indicated generally at 3.

The metering device is operated by air under pressure supplied via duct5, a valve-cock 4 and a manual pressure-reducing valve or control cock6. The metered mixture is discharged through an outlet duct 7 to whichthe injection pipe is connected.

The hopper is closed, at the top, by a cover 8 having a central outletopening or throat 9 for introduction of the mixture into the hopper.

The metering and injection system comprises a cylinder 10 (FIGS. 3-5) ofaluminum alloy, in which are upper and lower openings 10a and 10b whichare diametrically opposed and have a diameter equal to that of theoutlet opening of hopper 1.

Cylinder 10 is connected to the hopper by means of a collar 11 having atruncated conical portion to fit the conical base portion of the hopper.

Cylinder 10 is closed at its ends by knurled screw plugs 12 and 15, theplug 12 having a threaded axial socket for connection thereto of apipeline from the pressurized air cylinder with the control circuit.

In the cylinder 10 is a stainless steel piston member including a hollowfront section 13a and a solid rear section 13b interconnected by anaxial rod 130, the annular chamber C enclosed between which has an axiallength equal to the diameter of the discharge opening in the collar 11.

The solid part 13b of the piston is provided with a spigotted end 13d onwhich is located one end of a spring 14 whose other end is engaged in anaxial recess 15 in the plug 15. In a counter bore in the plug 15 is awasher 16 of resilient material, which acts as a damper for the piston.

Vent holes 17 18 are provided respectively in the front end of thecylinder 10 and in the closure plug 15 to permit of the escape or entryof air during the piston movements.

Secured to the underside of the cylinder is a cylindrical body part 19housing the metering device, in the form of a plunger 20. The axis ofpart 19 is aligned with the vertical axis of the outlet opening of thehopper and the cylinder opening 100 and 10b and at its upper end thebody 19 has an opening 19a of the same diameter as the opening 10b ofthe cylinder 10, while its open lower end has slidably mounted thereinthe plunger 20, which is axially adjustable in relation to a calibratedscale.

The plunger 20 is formed with a truncated conical recess 20' extended bya manifold 21, which is provided with an external thread to receive anelbow 7 or other member for connection of the metering device to adischarge line 22 (FIG. 1) for evacuating the metered material.

The plunger 20 is fixedly secured in its adjusted position by a screw 23and wing nut 24, the screw projecting through a helical cam slot 24 inthe cylinder wall 19. It is thus possible to fix the plunger 20 in aposition corresponding to a required volume as indicated by thegraduated scale S which may be glued onto the body 19 or engraved uponit.

Holes 26 and 27 drilled respectively in the cylinder 10 and in the upperwall of the metering cylinder permit of communication to be establishedbetween the two chambers when the piston has been moved to its closedposition as shown in FIG. 5.

In operation, assuming that the double piston 13a, 13b is in itsposition of rest shown in FIG. 4, where it is held by the spring 14, thechamber or transfer passage C enclosed therebetween coincides with theopenings 10a and 10b of the cylinder. In this position the material tobe distributed in successive doses falls by gravity from the hopper 1into the cup shaped interior 20' of the metering plunger 20 which hasbeen adjusted to a position (by reference of screw 23 to scale S)corresponding to the desired volume as indicated above.

To effect the injection of material, e.g., ammonium nitrate, thevalve-cock 4 is actuated so as to allow compressed air to enter thecylinder 10. The air then pushes the pistons 13a, 13b against thecompression spring 14 until part 13b of the piston comes to abut againstthe resilient washer 16 of the end plug 15.

In this position, shown in FIG. 5, the front section 13a of the pistoncloses the orifices 10a and 10b of the cylinder, thus effectivelypreventing further flow of material into the metering device. 'When inthis position the holes 26 and 27 register and compressed air can thenenter the cylinder 19 and eject the measured amount of materialpreviously transferred thereto and contained in the injection manifold.

When the lever of valve-cock 4 is released the return spring 14 forcesthe piston back to its initial position shown in FIG. 4 and the cycle isable to begin again.

The apparatus is thus capable of distributing material similar to thatquoted in the example, that is to say, ammonium nitrate in the form of arelatively dry granular mixture in spite of it being mixed with fueloil. There is no danger of flow of the substance into the elbow 7, thestabilization slope in this being in the neighborhood of 350.

In the event of the material being in past from with a more fluidconsistency, it is possible to add to the metering device apositively-driven mechanical closure valve.

The metering apparatus of this invention may be composed of elementsmade of stainless steel or other stainless materials or materials whichare resistant to corrosion. It is of relatively small size, which makesit portable and movable.

The metering apparatus which is the object of the invention may be usedto fill containers of all kinds, but it is more particularly applicablein pyrotechnics for the injection of charges into blast holes.

It operates under continuous pressure and uses compressed air only atthe moment of injection of precise and regular charges, whatever be thediameter of the blast hole drilled. This prevents waste of ammoniumnitrate and makes more accurate shots possible, because the injecteddoses can be adjusted as the user desires and on the actual site of theshots.

What is claimed is:

1. A metering apparatus which is portable for supply of low viscositymaterials in measured quantities comprising the combination of a hopperfor the material to be metered, said hopper having a bottom opening fordischarge of material by gravity therefrom, a horizontally extendingcylinder having an inlet orifice and an outlet orifice, and a pistonmember mounted therein, said piston member having a first section and asecond section axially spaced from one another to define a transferpassage, said inlet orifice being connected to said hopper bottomopening to permit of flow by gravity of material from the hopper intosaid transfer passage, a metering device including a chamber having anupper opening and a bottom opening for discharge of metered quantitiestherefrom, said upper opening being connected to said outlet orifice,means urging said piston to a normal open position in which material canflow by gravity from the hopper through the transfer passage into themetering chamber, a metering plunger displaceably mounted within themetering chamber by which its volumetric capacity can be varied to givea predetermined metered amount, means for manually adjusting theposition of said plunger, pneumatically actuated means for effectingdisplacement of the piston member to a position in which said firstsection thereof closes the opening from said hopper to cut off flow ofmaterial therefrom and permit discharge of the measured quantity ofmaterial within the metering chamber, said cylinder and metering chamberhaving ports to permit air pressure within the cylinder to betransmitted to the metering chamber, whereby discharge of material fromthe metering chamber takes place under pressure.

2. A metering apparatus as claimed in claim 1 comprising a meteringchamber in which the metering plunger comprises a recess of taperingwidth to assist in discharge of material through the outlet opening inthe bottom thereof.

3. A metering apparatus as claimed in claim 1 comprising a cylinderwhich is open-ended and having a plug secured in each open end thereof,the plug at one end having a bore for connection to a source of airunder pressure and the plug at the opposite end having a-recess toaccommodate a return spring, one end of which abuts the second sectionof the piston.

4. A metering apparatus as claimed in claim 1 in which admission of airto the cylinder is controlled by a manually operated valve.

5. A metering apparatus as claimed in claim 1 wherein the meteringdevice comprises a cylinder within which the metering plunger isdisplaceable and said plunger has attached thereto a stud forco-operation with a cam face in the wall of the metering cylinder.

6. A metering apparatus as claimed in claim 5 in which a helical camslot is provided in the wall of the metering cylinder and the stud is ofa length to project through the slot and a scale is provided on theouter face of said wall to indicate the position of adjustment of theplunger.

1. A metering apparatus which is portable for supply of low viscositymaterials in measured quantities comprising the combination of a hopperfor the material to be metered, said hopper having a bottom opening fordischarge of material by gravity therefrom, a horizontally extendingcylinder having an inlet orifice and an outlet orifice, and a pistonmember mounted therein, said piston member having a first section and asecond section axially spaced from one another to define a transferpassage, said inlet orifice being connected to said hopper bottomopening to permit of flow by gravity of material from the hopper intosaid transfer passage, a metering device including a chamber having anupper opening and a bottom opening for discharge of metered quantitiestherefrom, said upper opening being connected to said outlet orifice,means urging said piston to a normal open position in which material canflow by gravity from the hopper through the transfer passage into themetering chamber, a metering plunger displaceably mounted within themetering chamber by which its volumetric capacity can be varied to givea predetermined metered amount, means for manually adjusting theposition of said plunger, pneumatically actuated means for effectingdisplacement of the piston member to a position in which said firsTsection thereof closes the opening from said hopper to cut off flow ofmaterial therefrom and permit discharge of the measured quantity ofmaterial within the metering chamber, said cylinder and metering chamberhaving ports to permit air pressure within the cylinder to betransmitted to the metering chamber, whereby discharge of material fromthe metering chamber takes place under pressure.
 2. A metering apparatusas claimed in claim 1 comprising a metering chamber in which themetering plunger comprises a recess of tapering width to assist indischarge of material through the outlet opening in the bottom thereof.3. A metering apparatus as claimed in claim 1 comprising a cylinderwhich is open-ended and having a plug secured in each open end thereof,the plug at one end having a bore for connection to a source of airunder pressure and the plug at the opposite end having a recess toaccommodate a return spring, one end of which abuts the second sectionof the piston.
 4. A metering apparatus as claimed in claim 1 in whichadmission of air to the cylinder is controlled by a manually operatedvalve.
 5. A metering apparatus as claimed in claim 1 wherein themetering device comprises a cylinder within which the metering plungeris displaceable and said plunger has attached thereto a stud forco-operation with a cam face in the wall of the metering cylinder.
 6. Ametering apparatus as claimed in claim 5 in which a helical cam slot isprovided in the wall of the metering cylinder and the stud is of alength to project through the slot and a scale is provided on the outerface of said wall to indicate the position of adjustment of the plunger.